He now has two career complete games in 57 starts, and both have come against the Mets.

Lannan (7-7) did not walk a batter and struck out one. He did not give up an extra-base hit and only once did a Met reach second base.

The left-hander's performance snapped Washington's six-game losing streak. The win also gave interim manager Jim Riggleman his first win in six games since replacing the fired Manny Acta at the All-Star break.

"I can't lie to you, it feels good to win a ballgame," Riggleman said. "John was so outstanding tonight that he made it easy for the staff and myself to do what we do -- just watch him work."

Lannan felt Riggleman deserved the game ball after the win. The pitcher wasn't too concerned about giving up the keepsake.

"I'm pretty sure I can find a ball to put that stat on it," Lannan said.

New York has been shut out five times in its last 13 games and seven times in 26 games since Carlos Beltran went on the DL on June 22. The Mets have been blanked nine times this year, tying Atlanta and the Chicago White Sox for the major league lead.

"Very, very, very staggering stats by today's standards in baseball," New York manager Jerry Manuel said. "You see teams scoring a lot of runs, and we seem to be saving ours for the next day."

The Mets fell a season-high 10 games behind the Phillies.

The Nationals' last complete-game shutout was by Pedro Astacio on Aug. 15, 2006 in a two-hit 5-0 win against Atlanta. This was the first shutout by any pitcher at Nationals Park, which opened last season.

Oliver Perez (2-3) gave up four earned runs in six innings, walking six and hitting a batter.

The only time New York mounted any sort of offensive threat was in the third inning, when singles by Perez and Luis Castillo gave the Mets runners on first and second with two outs. David Wright hit a long fly ball that Washington centerfielder Nyjer Morgan leapt to catch against the centerfield fence to end the inning.

"That was the game-changer for me," Lannan said.

Washington was able to capitalize on Perez's lack of control in the middle innings.

Perez hit Morgan to lead off the fifth and Zimmerman walked before Dunn's RBI single and Josh Willingham's sacrifice fly gave Washington two more runs.

That was more than enough for Lannan, who retired 17 of the final 19 batters.

"He seems like he doesn't really stick to one game plan," Wright said. "He goes at you a number of different ways, really mixes it up, throws a lot of strikes."

Lannan didn't get a strikeout until pinch-hitter Angel Berroa fanned in the eighth inning, instead relying on ground balls. He got 17 ground-ball outs, including two double plays.

"I've never considered myself a dominating pitcher," Lannan said. "I don't think the guys over in the Mets clubhouse are like, 'Wow, that guy dominated me.' I just made good pitches, down in the zone."

Notes

Mets OF Gary Sheffield has not played since leaving Friday's game with hamstring cramps. Manuel said Sheffield will be available for "emergency pinch-hitting" until Friday. If Sheffield is still limited Friday, a trip to the DL is "a possibility," Manuel said.

The Mets entered the game with four home runs in July, fewest in the majors. The Nationals were among four teams tied for second-least with 10.

Copyright 2015 by STATS LLC and The Associated Press. Any commercial use or
distribution without the express written consent of STATS LLC and The
Associated Press is strictly prohibited.